Balancing Water Chemistry in a New 150-Gallon Pond

New pond with UV+biofilter: ammonia 0.50, nitrite 0.25, KH dropping (71→53), pH 7.5.

Action plan:

1. Monitor ammonia daily—do 20% water changes if >0.
2. Add KH+ (sodium bicarbonate) slowly: 1°dKH per 2 days.
3. Add filter-start bacteria.
4. Stop feeding until ammonia/nitrite hit 0.
5. Weekly 5–10% water changes once stable.
6. Test tap water—it may contribute ammonia.

Filters take 1–2 years to mature. Small, frequent adjustments prevent fish stress.